Carburetor



Sept. 7, 1937.

H. H. TIMIAN CARBURETOR Filed March 1, 1934 2 Sheets-Sheet 1 IIQI III]

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P ATTORNEY i -Patented Sept. 7, 1937 PATENT" OFFICE- aoazaaz cannons-r01:

Harold H. Timian, Lake Orion, Mich, assignor to Bendix Aviation Corporation, South Bend, Ind., a corporation of Delaware Application March 1, 1934, Serial No. "113,471

1 Claim.

A still further obiect of the invention is to provide an improved carbureting unit of simplifled construction which may be economically manufactured and which will be economical and positive in operation.

Another object is to provide a carbureting device in which the fuel level in the float chamber will be regulated by means of a float actuated suction responsive check valve communicating with the fuel pump so that the fuel level will be held continually between two limits determined 5 by the setting of the check valve.

Other objects and advantages of the invention will be apparent from the following detailed description, and from the illustrative embodiments of the invention in the accompanying drawings,

which are submitted merely for purposes of illustration and are not intended to define the scope of the invention, referencebeing had for that purpose to the subiolned claim.

In the drawings, wherein similar reference characters refer to similar parts throughout the several views:

Figure 1 is an elevation showing one form of carbureting device embodying the invention, fitted to an internal combustion engine;

Figure 2 is a vertical section of the same;

Figure 3 is a diagrammatic view showing a portion of the diaphragm actuating mechanism;

and

Figure 4 is a vertical section showing another form of the invention.

Dressed valve member 26 when the fuel level in float chamber l8 rises to a given level. Valve member 26 will then be urged upward by float 2l| compressing spring 28 and raising disk 30 from its seat 82 and allowing suction from inlet manifold I2 transmitted through duct 34 to be vented to the atmosphere by means of passage 86, cross bore 38, through chamber 48 and out vent ports 42. Chamber 40 is filled with loose packing material 44 to form an air cleaner.

When valve member 26 is closed the suction transmitted through duct 34 is transmitted by means of duct 44 to a fluid tight chamber 46 in which a flexible diaphragm 48 made of leather or other flexible material forms one wall, The diaphragm is fixed at its outer rim between two surfaces 50- and 62 fixed together by any convenient fastening means 54, and is actuated in one direction by suction from duct 44 and in the opposite direction by means of a coiled spring 56. Diaphragm 48 is engaged between a spring seat 58 and a flat disk 60 mounted on a threaded stud 62 fitted with a lock nut 64.- Threaded stud 62 is provided with a shank 66 and a cross member 68, better illustrated in Figure 3. Shank 66 fits into a groove 12 formed between a pair of ears 10 carried by a guide 14. Guide 14 is slidably mounted in a cylinder 86 provided with a passage 82 communicating with chamber 84 which communicates with atmosphere by means of vent 86. Chamber 84 is filled with loose packing material 88 to form an,alrcleaner.

A liquid pumping chamber 90 is provided on one side of diaphragm 48 and communicates with supply tank 16 by means of duct 92 fitted with gravity seating disk check valve 94 having a stop member 96 to prevent disk 84 from moving so far out of place that it could not return. The

1 upper portion of chamber 90 is fitted with a similar disk check valve 98 provided with a stop member I and communicates with the bottom of float chamber i8 by means of duct I02.

The operation of this device is as follows. Assume that the engine is running and that float 20 is in the position shown in Figure 2. Slidable valve member 26 is held in its uppermost position by float 20, compressing spring 28 so that suction transmitted from intake manifold l2 through duct is vented to atmosphere through passage 36, cross bore 35, chamber 40 and vent ports 42. In this position no fuel will be pumped and the engine ill will operate on the fuel present in float chamber l8 until the liquid level therein drops to such a point that float 20 will allow valve member 26 to move downward until disk 30 is urged against its seat 82 by spring 20. Passage 36 is then closed to suction transmitted through duct 34 and it will be transmitted by means of duct 44 to fluid tight chamber 46 where a partial vacuum will becreated which will draw diaphragm 48 to the right compressing spring 56 and drawing fuel from storage tank l6 through duct 82 into chamber 80. As diaphragm 48 moves to the right, guide I4 moves in cylinder 80 until cross bore 18 is lined up with passage 82 whereupon chamber 46 is vented to atmosphere by meansof longitudinal bore I6, cross bore 18, chamber 84 and vent 86. When chamber 46 is thus vented coiled spring 56 urges diaphragm 48 to the-left closing check valve 84, opening check valve 80 and pumping fuel from chamber 80 through duct I02 to float chamber I8.

As soon as guide I4 moves to the left cross 20 bore I8 and passage 82 are thrown out of alinement and suction from duct 44 will again be exerted in chamber 46 to actuate diaphragm. This process continues until the fuel level in float chamber I8 rises to such a point that float 20 lifts valve member 26, thereby venting the system through the passages associated with the top of float chamber I8, and renders the fuel pumping apparatus inoperative.

Figure 4 illustrates a device similar in many respects to that disclosed in Figure 2, but having the fuel pump formed as an integral part of the carburetor instead of being formed as a separate unit connected by ducts as disclosed in Figure 2.

Figure 4 illustrates a carbureting device of the down-draft type having a main inductionpassage I20 with a choke valve I22 to regulate the amount of air admitted through air horn I24. Fuel is admitted to induction passage I20 from float chamber I25 by means of a fuel discharge nozzle I26 terminating in the most restrictedsage I20 posterior to throttle valve I22 by means of duct I34 which leads to a suction actuated Ifuel pump I38 similar to that disclosed in connection with Figure 2. An auxiliary duct I36 communicates with duct I34 and leads to a downwardly extending passage I40 leading to float chamber I25. Passage I40 receives a slidable valve member I42 having a disk-like member I 44 flxed thereto. Disk member I44 cooperates with a seat I46 to close auxiliary duct I36 when valve member I42 is urged downwardly by spring I 50. Valve member I42 is actuated by float I48 which is sensitive to variation in fuel level in chamber I25.

When the fuel level in chamber I25 is high the top of float I48 engages the end of valve member I42 and forces it up compressing spring I50 and raising disk I44 from its seat I46 so that.

suction from duct I34 may be by-passed through float chamber I25 thereby interrupting the action of fuel pump I38 until the fuel level in float chamber I25 has lowered to such an extent that disk I44 may be urged against its seat I46 by spring I50 whereupon suction will again be transmitted to pump I38 through duct I34.

Fuel pump I38 is identical in construction and operation with that disclosed in connection with Figures 2 and 3. Corresponding parts have been numbered the same as in those figures. Fuel is transmitted from chamber to float chamber I25 by means of duct I52 communicating therewith.

I claim:

In combination a carburetor for an engine having a source of suction, a fuel reservoir, a float controlling the fuel level in the reservoir, a differential pressure actuated fuel pump comprising a diaphragm, a fluid pumping chamber, and an actuating chamber, connecting means between the actuating chamber and the source of suction, yielding means urging the diaphragm toward one extreme position, venting means operable to vent the actuating chamber when the diaphragm approaches one extreme position, and means operable by said float to vent the connecting means and render the fuel pump inoperative when said float approaches one extreme position.

HAROLD H. TIMIAN. 

